must be able to annihilate both time and space, and to deal with millions of
individuals together in one group or class. Only in this way can our thinking go
beyond that of the lower animals; for a wise rat, even, may come to see the
relation between a trap and danger, or a horse the relation between pulling with
his teeth at the piece of string on the gate latch, and securing his liberty.
But it takes the farther-reaching mind of man to invent the trap and the latch.
Perception alone does not go far enough. It is limited to immediately present
objects and their most obvious relations. The perceptual image is likewise
subject to similar limitations. While it enables us to dispense with the immediate
presence of the object, yet it deals with separate individuals; and the world is too
full of individual objects for us to deal with them separately. It is in conception,
judgment, and reasoning that true thinking takes place. Our next purpose will
therefore be to study these somewhat more closely, and see how they combine in
our thinking.
4. THE CONCEPT
Fortunately for our thinking, the great external world, with its millions upon
millions of individual objects, is so ordered that these objects can be grouped
into comparatively few great classes; and for many purposes we can deal with
the class as a whole instead of with the separate individuals of the class. Thus
there are an infinite number of individual objects in the world which are
composed of matter. Yet all these myriads of individuals may be classed under
the two great heads of inanimate and animate. Taking one of these again: all
animate forms may be classed as either plants or animals. And these classes may
again be subdivided indefinitely. Animals include mammals, birds, reptiles,
insects, mollusks, and many other classes besides, each class of which may be
still further separated into its orders, families, genera, species, and individuals.
This arrangement economizes our thinking by allowing us to think in large
terms.
The Concepts Serve to Group and Classify.—But the somewhat complicated
form of classification just described did not come to man ready-made. Someone
had to see the relationship existing among the myriads of animals of a certain
class, and group these together under the general term mammals. Likewise with
birds, reptiles, insects, and all the rest. In order to accomplish this, many
individuals of each class had to be observed, the qualities common to all
members of the class discriminated from those not common, and the common